Nasopharyngeal carcinoma (NPC) is endemic in southern China and the incidence is increasing in North America. NPC is directly associated with Epstein-Barr Virus (EBV) where it exists in every tumor cell in a tightly controlled latent state. EBV-associated NPC is a promising target for cancer immunotherapy. EBV viral proteins can serve as unique foreign tumor antigens for cytotoxic T cells (CTLs). Immunotherapy with EBV-specific T cell populations expanded in vitro is effective in PTLD, however translating that success to other EBV-associated malignancies, such as NPC, is challenging. Despite the limited repertoire of potential CTL targets expressed in NPC, a recent phase I trial showed that adoptive transfer of ex vivo expanded autologous EBV-specific T cells was safe and provided evidence for activity in a small number of patients with relapsed or refractory disease. In order to develop improved immunotherapy, a firm estimation of clinical efficacy for EBV- specific immunotherapy in NPC is required. Further study is also necessary to more completely dissect the CTL response and identify the mechanisms underlying effective immunotherapy and mechanisms of enhancing the response in order to develop better therapeutic strategies. We propose a comprehensive clinical estimation and translational Phase II trial of ex vivo expanded EBV specific T cell therapy in patients with relapse NPC to (1) Estimate the overall response rate in patients with recurrent and/or metastatic EBV-associated NPC (2) Establish the repertoire and clinical correlates of response and (3) systematically study the contribution and potential impact of removing Tregs by CD25 depletion and/or inhibiting Treg activity. We will select a second treatment arm for a subsequent Phase IIb study based on the in vitro laboratory studies and in vivo clinical results from this translational estimation clinical trial. PUBLIC HEALTH RELEVANCE: Nasopharynx cancer is caused by a common virus that is present in all the tumor cells and causes the cancer. For some reason the patient can't eradicate the virus and the tumor cells, although most people do control the infection and don't get cancer. There is some evidence that artificially stimulating the patient's own immune cells with virus infected cells in a test tube can by-pass whatever is preventing the immune system from stopping the cancer. This creates a cellular anti-cancer vaccine that can be given back to the same patient and treat the cancer. We plan to study this process and see if we can improve the effectiveness of the therapy.